The molecular properties and composition of fullerene-containing polystyrenes prepared through evaporation of solvent from the combined solution of a polymer and C₆₀ in benzene have been studied by viscometry, translational isothermal diffusion, GPC, UV spectroscopy, and electrooptical Kerr effect measurements. With this procedure of C₆₀ introduction into the polymer, a partial depolymerization of the parent polystyrene takes place. It has been shown that the composites contain fullerene in two forms: a smaller part of C₆₀ is bound to macromolecules, while a larger part of C₆₀ is incorporated into the composition of low-molecularmass adducts-the products arising from the interaction of fullerene with fullerene-induced depolymerized polystyrene.